Physics Rotational & Circular Motion NUMS 2024
PMDC Verified Question 17 of 95
Sara goes around a circular track that has diameter of \( 20 \text{ m} \). If she runs around the entire track for a distance of \( 80 \text{ m} \). What is her angular displacement?
A
16 radians
B
18 radians
C
50 radians
D
8 radians
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: 8 radians
Concept:

Angular displacement evaluates the total distance traversed strictly against the radius of the circle.

Formula:

$$ \theta = \frac{S}{r} $$

Solution:

  • The diameter is \( 20 \text{ m} \), so the radius \( r = \frac{20}{2} = 10 \text{ m} \).
  • The linear distance traversed \( S = 80 \text{ m} \).
  • Substitute into the formula: \( \theta = \frac{80}{10} \).
  • This gives exactly \( 8 \text{ radians} \).


Why other options are incorrect:

  • Option A occurs if you wrongly divide the distance by the diameter (80/20 = 4) and then randomly multiply by something, or misapply formulas. Wait, actually, if you use diameter, you get 4. No clear logic leads to A, B, or C except random guessing.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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